Spinal implants are typically implanted when the spine of a patient is dysfunctional (e.g., misaligned or degenerated). Following surgery and/or during or after the healing process, muscular and skeletal alignment or adjustment may occur. Such alignments and adjustments may affect the patient's range of motion, the effectiveness, life expectancy, or performance of the existing spinal implant, and/or potentially cause deterioration of surrounding bones, discs, vertebrae, hips, knees, etc., or the existing implant. For example, when the abdominal and back muscles strengthen after an implant procedure, the spine may subsequently align or realign, causing the implant or its articulation faces to be impinged as a result of the alignment or realignment. Thus at times there is a need for spinal surgeons to revise (e.g., extend) an existing spinal implant installed in a patient during a prior surgical procedure. For example, a revision surgery may entail lengthening an existing implant so that it spans additional portions of the spine.
Revision-type surgeries have been developed, but difficulties with typical instrumentation and procedures remain. Ideal locations to anchor a revision implant may already be occupied by the existing implant, thereby requiring the medical practitioner to adjust, reposition, remove, or otherwise significantly disrupt the existing implant in order to insert the revision implant. Surgeons may also need to open up the region of the existing implant to obtain a better view of the surgical site. Such procedures are often performed subcutaneously (i.e., under the skin), and are highly invasive and require large incisions, such as in tissue and muscle, thereby increasing surgical time, patient trauma, blood loss, tissue damage, post-operative pain, recovery and healing periods, and treatment costs. Current methods to revise existing spinal implants also frequently entail the use of multiple and separate assemblies (e.g., various forms of screws, hook and or connectors linked by rods, wires, or plates), which can be inconvenient, reduce surgical accuracy; and further increase surgery time and costs. It would be desirable to reduce or eliminate these and other drawbacks of revising an existing implant by providing a revision implant having a minimal number of components and which may be installed in the spine of a patient percutaneously, improve placement in the spine of patient during surgery, and reduce or eliminate the need to significantly disrupt or remove the existing implant in order to achieve the desired revision.
The present invention satisfies the above-described needs and provides other benefits and advantages in a novel and nonobvious manner.